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Iee Transformation
For conversion of the ground current Iee in primary quantities, the device requires the
primary/secondary transformation ratio of the transformer. This is set at address 213
Ratios
FACTOR IEE.
At addresses 221 Unom PRIMARY and 222 Unom SECONDARY, information is entered
Nominal Values of
Voltage Transform-
regarding the primary nominal voltage and secondary nominal voltages (phase-to-
ers
phase) of the connected voltage transformers.
At address 223 UE CONNECTION the user specifies to the device which type of
Voltage Connec-
tion U
voltage is connected to the UE input. The device establishes from this information how
E
to process the input signal. The following table shows the interdependencies for each
protection function.
Table 2-1
UE Transformation
For conversion of the displacement voltage U
Ratio
quires the primary/secondary transformation ratio of the transformer delivering the UE
voltage. With the exception of the rotor earth fault protection, the 224 FACTOR UE has
an impact on those protection functions which process the UE input directly, as shown
in Table 2-1. For this ratio224 FACTOR UE the following generally applies:
In this context, U
U
is used, its division ratio also influences this factor. The following equation results for
the example in Section 2.1, unit transformer connection figure, with the power system
data selected there and an 1:5 voltage divider ratio
7UM61 Manual
C53000-G1176-C127-3
Setting Options for the UE Input and their Impact on the Protection Functions
Setting for UE CONNEC-
TION (Addr. 0223)
not connected
UE connected to any trans-
former
UE connected to broken
delta winding
UE connected to neutral
transformer
is the primary voltage (generally phase-ground voltage) and
VT, prim
is the secondary displacement voltage applied to the device. If a voltage divider
E, sec
90% Stator Earth Fault
Protection
Processing of U0 computed
value (exactly: √3 U0)
Processing of UE input
(e.g. earth fault protection
on transformer side)
Processing of UE input
Processing of UE input
to primary quantities, the device re-
E
2.3 Power System Data 1
Stator Earth Fault Protec-
tion with 3rd Harmonic
The 3rd harmonic is deter-
mined from the computed
U0 voltage (U0 3rd harm >
stage only usable).
–
Processing of UE input
Processing of UE input
35
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